[utils] `traverse_obj`: Various improvements

- Add `set` key for transformations/filters
- Add `re.Match` group names
- Fix behavior for `expected_type` with `dict` key
- Raise for filter function signature mismatch in debug

Authored by: Grub4K
pull/6139/head
Simon Sawicki 2 years ago committed by GitHub
parent 8b008d6254
commit 776995bc10
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23

@ -105,6 +105,7 @@ from yt_dlp.utils import (
sanitized_Request,
shell_quote,
smuggle_url,
str_or_none,
str_to_int,
strip_jsonp,
strip_or_none,
@ -2015,6 +2016,29 @@ Line 1
msg='function as query key should perform a filter based on (key, value)')
self.assertCountEqual(traverse_obj(_TEST_DATA, lambda _, x: isinstance(x[0], str)), {'str'},
msg='exceptions in the query function should be catched')
if __debug__:
with self.assertRaises(Exception, msg='Wrong function signature should raise in debug'):
traverse_obj(_TEST_DATA, lambda a: ...)
with self.assertRaises(Exception, msg='Wrong function signature should raise in debug'):
traverse_obj(_TEST_DATA, lambda a, b, c: ...)
# Test set as key (transformation/type, like `expected_type`)
self.assertEqual(traverse_obj(_TEST_DATA, (..., {str.upper}, )), ['STR'],
msg='Function in set should be a transformation')
self.assertEqual(traverse_obj(_TEST_DATA, (..., {str})), ['str'],
msg='Type in set should be a type filter')
self.assertEqual(traverse_obj(_TEST_DATA, {dict}), _TEST_DATA,
msg='A single set should be wrapped into a path')
self.assertEqual(traverse_obj(_TEST_DATA, (..., {str.upper})), ['STR'],
msg='Transformation function should not raise')
self.assertEqual(traverse_obj(_TEST_DATA, (..., {str_or_none})),
[item for item in map(str_or_none, _TEST_DATA.values()) if item is not None],
msg='Function in set should be a transformation')
if __debug__:
with self.assertRaises(Exception, msg='Sets with length != 1 should raise in debug'):
traverse_obj(_TEST_DATA, set())
with self.assertRaises(Exception, msg='Sets with length != 1 should raise in debug'):
traverse_obj(_TEST_DATA, {str.upper, str})
# Test alternative paths
self.assertEqual(traverse_obj(_TEST_DATA, 'fail', 'str'), 'str',
@ -2106,6 +2130,20 @@ Line 1
msg='wrap expected_type fuction in try_call')
self.assertEqual(traverse_obj(_EXPECTED_TYPE_DATA, ..., expected_type=str), ['str'],
msg='eliminate items that expected_type fails on')
self.assertEqual(traverse_obj(_TEST_DATA, {0: 100, 1: 1.2}, expected_type=int), {0: 100},
msg='type as expected_type should filter dict values')
self.assertEqual(traverse_obj(_TEST_DATA, {0: 100, 1: 1.2, 2: 'None'}, expected_type=str_or_none), {0: '100', 1: '1.2'},
msg='function as expected_type should transform dict values')
self.assertEqual(traverse_obj(_TEST_DATA, ({0: 1.2}, 0, {int_or_none}), expected_type=int), 1,
msg='expected_type should not filter non final dict values')
self.assertEqual(traverse_obj(_TEST_DATA, {0: {0: 100, 1: 'str'}}, expected_type=int), {0: {0: 100}},
msg='expected_type should transform deep dict values')
self.assertEqual(traverse_obj(_TEST_DATA, [({0: '...'}, {0: '...'})], expected_type=type(...)), [{0: ...}, {0: ...}],
msg='expected_type should transform branched dict values')
self.assertEqual(traverse_obj({1: {3: 4}}, [(1, 2), 3], expected_type=int), [4],
msg='expected_type regression for type matching in tuple branching')
self.assertEqual(traverse_obj(_TEST_DATA, ['data', ...], expected_type=int), [],
msg='expected_type regression for type matching in dict result')
# Test get_all behavior
_GET_ALL_DATA = {'key': [0, 1, 2]}
@ -2189,6 +2227,8 @@ Line 1
msg='failing str key on a `re.Match` should return `default`')
self.assertEqual(traverse_obj(mobj, 8), None,
msg='failing int key on a `re.Match` should return `default`')
self.assertEqual(traverse_obj(mobj, lambda k, _: k in (0, 'group')), ['0123', '3'],
msg='function on a `re.Match` should give group name as well')
if __name__ == '__main__':

@ -5424,6 +5424,9 @@ def traverse_obj(
The keys in the path can be one of:
- `None`: Return the current object.
- `set`: Requires the only item in the set to be a type or function,
like `{type}`/`{func}`. If a `type`, returns only values
of this type. If a function, returns `func(obj)`.
- `str`/`int`: Return `obj[key]`. For `re.Match`, return `obj.group(key)`.
- `slice`: Branch out and return all values in `obj[key]`.
- `Ellipsis`: Branch out and return a list of all values.
@ -5432,6 +5435,8 @@ def traverse_obj(
- `function`: Branch out and return values filtered by the function.
Read as: `[value for key, value in obj if function(key, value)]`.
For `Sequence`s, `key` is the index of the value.
For `re.Match`es, `key` is the group number (0 = full match)
as well as additionally any group names, if given.
- `dict` Transform the current object and return a matching dict.
Read as: `{key: traverse_obj(obj, path) for key, path in dct.items()}`.
@ -5441,6 +5446,8 @@ def traverse_obj(
@param default Value to return if the paths do not match.
@param expected_type If a `type`, only accept final values of this type.
If any other callable, try to call the function on each result.
If the last key in the path is a `dict`, it will apply to each value inside
the dict instead, recursively. This does respect branching paths.
@param get_all If `False`, return the first matching result, otherwise all matching ones.
@param casesense If `False`, consider string dictionary keys as case insensitive.
@ -5466,16 +5473,25 @@ def traverse_obj(
else:
type_test = lambda val: try_call(expected_type or IDENTITY, args=(val,))
def apply_key(key, obj):
def apply_key(key, test_type, obj):
if obj is None:
return
elif key is None:
yield obj
elif isinstance(key, set):
assert len(key) == 1, 'Set should only be used to wrap a single item'
item = next(iter(key))
if isinstance(item, type):
if isinstance(obj, item):
yield obj
else:
yield try_call(item, args=(obj,))
elif isinstance(key, (list, tuple)):
for branch in key:
_, result = apply_path(obj, branch)
_, result = apply_path(obj, branch, test_type)
yield from result
elif key is ...:
@ -5494,7 +5510,9 @@ def traverse_obj(
elif isinstance(obj, collections.abc.Mapping):
iter_obj = obj.items()
elif isinstance(obj, re.Match):
iter_obj = enumerate((obj.group(), *obj.groups()))
iter_obj = itertools.chain(
enumerate((obj.group(), *obj.groups())),
obj.groupdict().items())
elif traverse_string:
iter_obj = enumerate(str(obj))
else:
@ -5502,7 +5520,7 @@ def traverse_obj(
yield from (v for k, v in iter_obj if try_call(key, args=(k, v)))
elif isinstance(key, dict):
iter_obj = ((k, _traverse_obj(obj, v)) for k, v in key.items())
iter_obj = ((k, _traverse_obj(obj, v, test_type=test_type)) for k, v in key.items())
yield {k: v if v is not None else default for k, v in iter_obj
if v is not None or default is not NO_DEFAULT}
@ -5537,11 +5555,24 @@ def traverse_obj(
with contextlib.suppress(IndexError):
yield obj[key]
def apply_path(start_obj, path):
def lazy_last(iterable):
iterator = iter(iterable)
prev = next(iterator, NO_DEFAULT)
if prev is NO_DEFAULT:
return
for item in iterator:
yield False, prev
prev = item
yield True, prev
def apply_path(start_obj, path, test_type=False):
objs = (start_obj,)
has_branched = False
for key in variadic(path):
key = None
for last, key in lazy_last(variadic(path, (str, bytes, dict, set))):
if is_user_input and key == ':':
key = ...
@ -5551,14 +5582,21 @@ def traverse_obj(
if key is ... or isinstance(key, (list, tuple)) or callable(key):
has_branched = True
key_func = functools.partial(apply_key, key)
if __debug__ and callable(key):
# Verify function signature
inspect.signature(key).bind(None, None)
key_func = functools.partial(apply_key, key, last)
objs = itertools.chain.from_iterable(map(key_func, objs))
if test_type and not isinstance(key, (dict, list, tuple)):
objs = map(type_test, objs)
return has_branched, objs
def _traverse_obj(obj, path, use_list=True):
has_branched, results = apply_path(obj, path)
results = LazyList(x for x in map(type_test, results) if x is not None)
def _traverse_obj(obj, path, use_list=True, test_type=True):
has_branched, results = apply_path(obj, path, test_type)
results = LazyList(x for x in results if x is not None)
if get_all and has_branched:
return results.exhaust() if results or use_list else None

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